In order to test the effectiveness of a new vaccine, 50 volunteers are selected and divided into two groups. One group is the control group and the other is the experimental group. Both groups are given a pill to take that is identical in size, shape, color and texture.
Based on the experiment scenario:
1. Describe the control group.
2. Describe the experimental group.
3. What variable is kept constant?
4. What variables are being changed?
Answer in at least 4 complete sentences.